#10182: lookupIfaceGlobal crash with SOURCE import -------------------------------------+------------------------------------- Reporter: simonpj | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.12.1 Component: Compiler | Version: 7.8.4 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by ezyang): I can reproduce with an even more minimized test-case, on a stage 2 quick build: {{{ module T8743 where class ToRow a instance ToRow () }}} {{{ module T8743 where import {-# SOURCE #-} T8743 () class ToRow a instance ToRow () where }}} With some more tracing you can get a clue: `tcIfaceGlobal` is being called because GHC is trying to report a duplicate instance error. That certainly should not happen! So in one-shot compilation, GHC is seeing an instance in its environment that is NOT supposed to be there. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10182#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler